This invention relates, in general, to obstetric devices, and, in particular, to obstetric devices which are used to calculate the gestation period.
In the prior art various types of devices have been proposed. For example, U.S. Pat. No. 2,513,196 to Morse discloses a rhythm calculator with a yearly calendar divided in months on the face of a circular case.
U.S. Pat. No. 5,496,070 to Thompson discloses a calendar monitoring system which includes a flat monitoring strip divided into months.
U.S. Pat. No. 5,777,905 to Dowdle et al discloses an electronic calculator for calculating obstetrical data.
U.S. Pat. No. 5,673,860 to Denis et al discloses a pocket sized electronic calculator for calculating gestational information.
During pregnancy, it is often desirable for the obstetrician to quickly and accurately calculate the patient""s prospective birth date, as well as the approximate calendar dates for various other stages of the pregnancy. This permits the doctor and the patient to plan the patient""s schedule and to, also, plan other activities during the pregnancy such as workups and ultrasound tests. Traditionally, obstetricians have performed these calculations with a revolving wheel, slide rule type apparatus, such as shown in FIG. 1.
However, conventional birth date calculators exhibit a number of disadvantages. The inner and outer scales are in small print and difficult to read. Moreover, the doctor must realign the inner wheel with the outer ring for each patient. This tedious and time consuming procedure my have to be repeated a large number of times each day, depending on the number of patients that the obstetrician sees.
In addition, the obstetrician often manipulates the birth date calendar/calculator with one hand, while holding the patient""s medical chart in the other hand. As the obstetrician""s attention shifts back and forth between the chart and calculator, the inner wheel on the calculator may shift out of position. Also, with use the calculator wheels become sloppy and can give the obstetrician a false reading.
Due to these factors conventional revolving calculators are prone to errors. A faulty pregnancy timetable can cause the patient to undertake undesirable activities which can pose inconvenience or a serious medical risk.
The present invention is directed to a device which has a calendar corresponding to the weekly duration of conception and date of delivery and a second calendar which is positioned to avoid unnecessary manipulation of the wheel.
It is an object of the present invention to provide a new and improved obstetric device.
It is an object of the present invention to provide a new and improved obstetric device which has a calendar for measuring the weekly duration of conception and date of delivery.
It is an object of the present invention to provide a new and improved obstetric device which has a calendar which is easier and more convenient to use.
These and other objects and advantages of the present invention will be fully apparent from the following description, when taken in connection with the annexed drawings.